\begin{table}%T3
\caption{Column density ratios$^1$.}\label{t3}
%\centerline
{
\begin{tabular}{lcc}
\hline\hline
Source & $N$(\hcop)/$N$(\hocp) & $N$(\hocp)/$N$(OH) \\ 
\hline
B0355+508 & 72(9) & $6.1(0.7)\times10^{-4}$\\
B0415+379 & 117(12)& $2.6(0.3)\times10^{-4}$\\
B0528+134 & $>$30 & ${<}1.6\times10^{-3}$ \\
B1730-130 & $>$18 & ${<}4.3\times10^{-3}$ \\
B2200+420 & 70(24) & $6.5(2.1)\times10^{-4}$\\
\hline
\end{tabular}}
\par
\medskip
$^1$ Limits are $2\sigma$.
\end{table}